1. Field of the Invention
This invention relates to electrical connectors and in particular to safety-type electrical connectors for preventing operation of an electrical appliance under certain conditions.
2. Description of the Prior Art
In certain electrical appliances, such as television receivers, the electrical components are disposed fully within an outer housing. An access opening is provided within the housing which is selectively closed by a closure panel removably secured to the housing to extend across the access opening. To prevent an unauthorized person from having access to the electrical apparatus when the closure panel is removed, the electrical power means is associated with the closure panel in such a way that removal of the panel effectively breaks the power supply. The conventional serviceman may energize the appliance with the closure panel removed by utilizing a special connector cord, whereas the ordinary owner or user of the apparatus, not having such a special connector cord, is normally protected from injury as by electrical shock, etc., by the prevention of application of electrical power to the appliance as an incident of the closure panel removal.
In a television receiver apparatus, certain portions of the apparatus are at relatively high voltage so that, for safety reasons, it is very important that the power supply be so interrupted when the closure panel is removed. A conventional arrangement in such television receivers has been to mount a female connector in such a way as to extend through the closure panel, and in such a position as to be electrically fitted onto a male connector carried by the rear of the receiver chassis within the cabinet when the closure panel is positioned across the housing opening. It has been found, however, that inasmuch as the female connector plug is disposed normally in such a manner as to make it difficult to ascertain its precise positioning relative to the male connector as the closure panel is brought to the opening-closing position, the plug is often engaged with the male connector pins laterally of the female sockets so that damage to the pins and plug results. Illustratively, the pins may be bent or deflected and the soft plug material deformed by such engagement.
Another problem in the conventional electrical appliance utilizing such a safety power supply connection means is the requirement that the means for securing the closure panel to the housing be accurately related to the position of the connector element carried in the appliance. Thus, conventionally, the closure panel is provided with a plurality of holes preselected to be aligned with securing portions of the housing when the connector element carried by the closure panel is aligned with the connector element of the apparatus. As the mounting of the connector element to the closure panel is substantially fixed, it is necessary that low tolerances be utilized in providing such accurate relationship during manufacture.
A number of prior art structures are disclosed in the prior art relating to the safety disconnect systems of such power supplies and apparatus for use therein. Thus, as shown in J. W. Myers U.S. Pat. No. 1,775,654, a safety cabinet is provided wherein the electrical connector is exposed through an opening in a hingedly mounted cover plate when the cover plate is disposed in a closed position across an access opening to the cabinet.
In the U.S. Pat. No. 1,645,261 of E. E. Sutherland, a terminal support is shown wherein male pins are mounted in a tubular guide which is outwardly flared at its distal end and which is exposed for observation by the user so as to permit facilitated connection of a female plug thereto.
H. H. Schulz, in U.S. Pat. No. 2,672,506, shows a mounting for television receiver sets wherein the male and female elements are provided in a long mounting tube which is suitably keyed so as to provide preselected alignment of the pin and socket elements thereof.
In A. H. Junkins U.S. Pat. No. 2,752,413, an electrical interlock is provided for use in conjunction with high voltage power supplies for television receivers. As shown therein, the female plug is connected to the male connector element when the rear cowling is secured to the housing. The Junkins patent teaches male pins projecting outwardly sufficiently to be engaged by the female plug laterally of the female plug sockets whenever the cowling is brought forwardly in other than accurately aligned original disposition and, thus, presents the serious problem of potential damage to the pins and plug discussed above.
W. R. Francis discloses, in U.S. Pat. No. 2,869,094, an adjustable panel mounting for a cord connector wherein a plug for a television receiver is adjustably mounted in an opening in the closure panel.
In U.S. Pat. No. 2,874,205 of C. F. Race, an electrical connector is shown for interlocking power connections in a portable radio or the like, which is similar to Junkins in teaching the projection of the male pins sufficiently outwardly to be engaged and damaged by inadvertent abutment of the female plug therewith laterally of the female plug sockets.
H. A. Pappano et al show, in their U.S. Pat. No. 3,052,865, a power cord adaptor which is generally similar to that of Francis in disclosing the use of a female plug adjustably mounted to a removable cover of an electrical apparatus.
W. R. Hicks, in U.S. Pat. No. 3.025,490, shows an electrical plug receptacle structure which is generally similar to that of Sutherland in providing a male pin connector which is exposed through the housing for electrical connection of a conventional female plug thereto.
H.J. Tenniswood, in U.S. Pat. No. 3,184,702, shows electrical connector apparatus wherein a frustopyramidal mounting means is provided for the male and female electrical connector means with the pyramidal configuration permitting lateral displacement of the plug-in socket prior to the interengagement therebetween while effecting an aligned relationship only when the pins and female elements are fully engaged.